1. Field of the Invention
The present invention relates to a working mechanism for a medical manipulator, and more particularly to a working mechanism for moving a distal-end working unit of a medical manipulator through filamentary members such as wires or the like.
2. Description of the Related Art
In laparoscopic surgery, a number of small holes are opened in a patient's abdomen or the like, and an endoscope, a forceps (or manipulator) or the like is inserted, and surgery is carried out while the surgeon observes an image from the endoscope on a monitor. In this type of laparoscopic surgery, owing to the fact that opening of the abdominal cavity is unnecessary, the burden on the patient is small, and the number of days required for the post-operative recovery and the number of days spent in the hospital can be significantly reduced. Therefore, laparoscopic surgical operations are expected to find an increased range of applications.
As disclosed in Japanese Laid-Open Patent Publication No. 2004-105451, for example, a manipulator system comprises a manipulator and a controller for controlling the manipulator. The manipulator comprises an operating unit which is manually operable and a working unit replaceably mounted on the operating unit.
The working unit (instrument) comprises a long joint shaft and a distal-end working unit (also referred to as an end effector) mounted on the distal end of the joint shaft. The operating unit has actuators (motors) for actuating the working unit at the distal end through wires. The wires are wound around respective pulleys at a proximal end side. The controller energizes the motors of the operating unit to cause the pulleys to move the wires back and forth.
The working unit is detachably mounted on the operating unit, so that the working unit can easily be processed, e.g., cleaned, after a surgical technique has been performed by the manipulator. In addition, various different working units, including a gripper, scissors, an electrosurgical knife, an ultrasonic knife, a medical drill, etc., are used in a laparoscopic surgical operation process. From the standpoint of being able to exchange these working units, a structure in which the working unit is detachable with respect to the operating unit also is beneficial.
In the working unit, the pulleys on the proximal end side are held in engagement with the rotatable shafts of the motors of the operating unit.
Japanese Laid-Open Patent Publication No. 11-012966 discloses a wire rope including a plurality of discriminant yarns mixed with an outermost layer and each covered with a metallic material which has a color different from the color of surrounding yarns.
The working unit includes pulleys and gears connected together by the wires for simply and reliably transmitting power.
Since the wires are subject to aging or changes due to usage, it is desirable to appropriately judge the degree of aging or usage-induced changes of the wires.